SINGAPORE (Reuters) - An old proverb states that 'revenge is a dish best served cold' but Dominika Cibulkova's service was smoking hot when she exacted vengeance on Angelique Kerber to claim the WTA Finals title on Sunday.

The German world number one had beaten the Slovakian in a tight three-setter a week ago when they faced off in round-robin play but Cibulkova saw enough in that losing effort to give her the confidence to turn the tables on her opponent in the final.

The 27-year-old hassled and harried Kerber from the very first game and after a 76-minute serving masterclass, Cibulkova was rolling around the court in stunned disbelief after claiming the biggest victory of her career, following a 6-3 6-4 triumph.

"I cannot find the right word in English to say it but in the first match I played against Angelique, you know, that first match gave me confidence that I can beat her," Cibulkova told reporters.

"My game is good enough to beat the world number one were the thoughts I had going into this final and I was feeling it from the first point until the last.

"It was only on the first match point, first two match points that I realised what the situation was but after that I just had one goal. I knew I could do it," she added after a lucky net-cord on her fourth championship point trickled over into Kerber's side of the court.

"I played good tennis like this quite a few times this year, but I couldn't wish to do it in any other match than this match, the final of the WTA Finals."

Cibulkova was making her debut at the elite eight-woman tournament but she performed like a seasoned veteran to dismantle a player who had won two grand slam titles in 2016, relying on a simple strategy and carrying it out to perfection.

"She has the best defensive game in the world but I knew I had the shots to hurt her -- my serve and my forehand," Cibulkova added with a grin.

"Actually I served really, really well, so I relied on that in some games and then my forehand in others.

"I just knew what I had to do. I didn't let her into the match today with my aggressive game. I had just one goal. I was going for it and I think it was tough for her to do anything on the court today."